Spinal deformity is corrected by fixing the vertebrae to a rod. The rod may be shaped to have a predetermined spine curvature. Devices such as screws, implants and anchors are inserted in the vertebrae, and the vertebrae is brought up or moved towards the rod through a rod fixation instrument. Thus, the spine is set to the rod.
In operation, the rod is introduced into a slot or channel of a rod fixation instrument such as a screw extender. The screw extender is coupled to a screw which is typically fixed to a pedicle of the vertebrae. Placing the vertebrae in a proper position with respect to the rod may require the vertebrae to be moved in three dimensions so as to align slots from a plurality of screw extenders with each other, wherein the rod may be passed through each of the slots. The rod fixation lay include a rod reducer element configured to fix the vertebrae to the rod.
Manipulation of a vertebra by a single rod fixation instrument may place an undesirable load on the vertebrae. Accordingly, a transverse link is used to couple two rod fixation instruments together, creating a construct, wherein the construct may be manipulated to position the vertebrae thus spreading the load among two rod fixation instruments.
The transverse links have a base and engagement members on opposite ends of the base. The base may be configured to axially displace the engagement members from each other a predetermined distance so as to accommodate the desired position of the respective screw extender. Current engagement members provide for limited movement in three dimensional space, thus manipulation of current verse links may impose an undue load on a vertebrae as the rod fixation instruments is restricted in movement. Accordingly, it remains desirable to have a transverse link wherein the engagement members provide for greater degree of movement in all three dimensions relative to the base. It furthers desirable to have a base configured to adjust the position of the engagement members with respect to each other.